Fig. 5: Clock output to descending neurons.

A Mono- and di-synaptic clock output to descending neurons. B Novel and C peptidergic descending neurons receiving direct clock input. All cell types are listed according to the strength of the clock input (from high to low). D–F Neurotransmitters expressed in clock neurons and their pre- and post-synaptic partners. D Neurotransmitter prediction from Eckstein et al. 2024⁵² based on electron microscopic data for presynaptic neurons of the clock network (left), the clock neurons (middle), and their postsynaptic neurons (right). E Most of the lateral clock neurons are cholinergic and most of the dorsal clock neurons are glutamatergic, while no clock neurons are GABAergic. Electron microscopy-based neurotransmitter predictions (Em) of clock neurons agree with F anatomical (An) expression mapping with T2A-Gal4 lines for neurotransmitter markers. G Weighted direct connections of clock neurons to descending neurons colored according to their neurotransmitter identity. s-CPDN₃ and LPN are strongly connected to three types of descending neurons. H Proportion of input synapses of the three descending neuron types that receive the strongest input from clock neurons. Each cell type gets about 25% input from clock neurons. I Schematic showing pathways via which CCAP-positive DNpe048 integrate time cues from the clock network with hunger and thirst signals to regulate feeding behavior. J Reconstructions of neurons that transmit time cues (black) and hunger and thirst-related signals (grey) to DNpe048 (magenta). K Pathways from clock neurons to descending neurons which could modulate the timing of reproductive behaviors. ACh acetylcholine, Glut glutamate, GABA γ-Aminobutyric acid, ChAT choline acetyltransferase, VGlut glutamate vesicle transporter, CCAP crustacean cardioactive peptide; Scale bar represents 5 µm. Source data for panels A, D, E, G, H, and K are provided in the Source Data file. Brain mesh is from Dorkenwald et al., 2024.